1. Field of the Invention
This invention relates to a device for the start-up control of bobbin creels for beam warpers or warping reels, the winding heads of which, disposed in rows and columns, each have associated with them a yarn monitor, which causes the yarn to be deflected by a stop-motion sensor, and a yarn gripper. More particularly in the present invention a yarn is clamped by the yarn gripper between a thrust block and a clamping jaw, which interacts with the thrust block and has limited motion. The clamping jaw is acted upon by a control element, especially a control spring, the clamping force of which in the clamping region between the clamping position and the open position can be controlled while the machine is starting up by an adjusting device, which acts jointly on all the yarn grippers.
2. Description of the Related Art
Such a device is known from the German Auslegesschrift 3,436,714. The known yarn gripper has a horizontal clamping jaw, which presses a horizontally directed yarn against the underside of a plate-shaped horizontal thrust block. This is done by a positioning rod, which likewise acts horizontally and which acts on one end of a leaf spring. When the yarn is clamped or braked, the other end of the leaf spring is clamped movably in the adjusting direction. The clamping jaw of the yarn gripper is fastened approximately at the center of this leaf spring. Due to this design, the clamping jaw executes a motion relative to this thrust block when the yarn is being acted upon. This relative motion is in the direction in which the adjusting rod is activated and thus in the longitudinal direction of the thrust block. The clamping force is also aligned at an angle to the thrust block, which results in complications while the machine is starting up. Especially with thin, twisted threads, and with and an appropriate throw of the shuttle the yarn may tend to untwist. This is associated with a corresponding displacement or movement of the yarn at the yarn braking point and prevents the desired correct influence on the braking of the yarn.